Drawing apparatus

ABSTRACT

A drawing apparatus comprising a head adapted to be placed in any position on the surface of drawing board through the agency of no outside supporter, a pair of rulers disposed at right angles to each other and pivotally connected to the head, and direction control means for automatically causing a predetermined one of the rulers to orient itself in a predetermined direction. If one haphazardly places the head in any position on the drawing board without paying attention to the direction in which it is oriented the rulers are controlled by the direction control means such that the predetermined one of the rulers orients itself in a predetermined direction. Accordingly, if the head is shifted on the drawing board, the rulers automatically orients itself in slaved relationship as if they moved in translation motion on the drawing board.

United States Patent [1 1 Shimizu Sept. 30, 1975 DRAWING APPARATUS [75] Inventor: Osamu Shimizu, Tokyo. Japan [73] Assignee: Mutoh Industry Ltd., Tokyo. Japan [22] Filed: Jan. 17, 1974 [21] Appl No.: 434,112

[30] Foreign Application Priority Data Jan. 31, 1973 Japan 48l2039 [52] U.S. Cl. 33/75 R; 33/76 R [51] Int. Cl.- B43L 13/00 [58] Field of Search 33/79, 76 R, 75 R [56] References Cited UNITED STATES PATENTS 3.339285 9/1967 Baker et a1 33/79 R 3,638,320 2/l972 Baker 33/79 R Primary E.\'aminerRichard E. Aegerter Assistant Examiner-Michael H. Thaler Attorney, Agent, or FirmWenderoth, Lind & Ponack 57 ABSTRACT A drawing apparatus comprising a head adapted to be placed in any position on the surface of drawing board through the agency of no outside supporter, a pair of rulers disposed at right angles to each other and pivotally connected to the head, and direction control means for automatically causing a predetermined one of the rulers to orient itself in a predetermined direction. If one haphazardly places the head in any position on the drawing board without paying attention to the direction in which it is oriented the rulers are controlled by the direction control means such that the predetermined one of the rulers orients itself in a predetermined direction. Accordingly, if the head is shifted on the drawing board, the rulers automatically orients itself in slaved relationship as if they moved in translation motion on the drawing board.

18 Claims, 27 Drawing Figures US. Patent Sept. 30,1975 Sheet10f18 3,908,275

U.S. Patent Sept. 30,1975 Sheet20f 18 3,908,275

US. Patent Sept. 30,1975 Sheet3of18 3,908,275

US. Patent Sept. 30,1975 Shet 5 of 18 U.S. Patent Sept. 30,1975 Sheet 6 of 18 FIG. 8

U.S. Patent Sept. 30,1975 SheetSof 18 3,908,275

.13 m we G? $2. a a. h ..m. m st o J 5 m wk N\ k Nm m mNm US. Patent Sept. 30,1975 Sheet 10 ofl8 3,908,275

U.S. Patent Sept. 30,1975 Sheet 11 of18 E" 5 m 2 m 4 1.1m y 1 m F 0 m w W 1 m FIG. 7

US. Patent Sept. 30,1975 Sheet 12 ofl8 3,908,275

U.S. Patent Sept."30,1975 Sheet 13 of 18 3,908,275

FIG. 20

U.S. Patent Sept. 30,1975 Sheet 14 of 18 3,908,275

US. Patent Sept. 30,1975 Sheet 17 0f18 3,908,275

NN 5N @VN ym 1 z 1 I 1 l 0mm 5N mm @mm DRAWING APPARATUS BACKGROUND OF THE INVENTION This invention relates in general to drawing apparatus constructed such that if the head is moved in any direction along the surface of a drawing board, the rulers connected to the head move in translation motion on the the drawing board. More particularly the invention relates to drawing apparatus of the type described which is characterized in that if the head is haphazardly placed through the agency of no outside supporter in any position on the drawing board without paying attentionto the'direction in which the head is oriented, then the direction in which the rulers are oriented is controlled such that one of the rulers automatically orients itself to form a predetermined angle with respect to a reference line. In this invention, the reference line refers to an imaginary elongated single straight line disposed in a plane parallel to the surface of the drawing board. More precisely, the reference line may be an imaginary line drawn parallel to the line of magnetic force of the earth; it may be an imaginary line formed on the surface of the drawing board disposed in an inclined position when a line perpendicular to the ground is projected onto the surface of the drawing board; it may be a line parallel to a copper wire disposed across the width of the drawing board, or it may be a line parallel to a signal receiving member disposed in a straight line on the surface of the drawing board.

Drawing apparatus of the prior art have been generally constructed such that their heads are each supported by a support arm of the pantagraph type, rails or other supporter and the head as well as the rulers are moved in translation motion along the surface of the drawing board by the guiding function of the supporter. When the head is supported by the arm or the rails, the drawing apparatus has the disadvantage of the rails or arm interfering with a drawing operation.

Other disadvantages of the prior art are that the drawing apparatus itself becomes bulky and heavy in weight when the head is connected to the rails or arm, and that the use of the arm or the rails places limitations on the range of movement of the head on the drawing board because a dead space is created on the drawing board which is beyond the reach of the rulers.

These disadvantages of the prior art can be eliminated only when the head is freed of its outside supporter and permitted to stand on its own so that its movement may not be controlled from outside.

SUMMARY OF THE INVENTION A general object of this invention is to provide a drawing apparatus comprising a head and a pair of rulers pivotally connected thereto, wherein when the head supported by no outside supporter is haphazardly placed on the surface of a drawing board without paying any attention to the direction in which it is oriented, an angle formed by a predetermined one of the pair of rulers with respect to the aforementioned reference line is automatically detected and the rulers are controlled to orient themselves to that the angle may correspond to an angle of a predetermined value, whereby the angle formed by the predetermined one of the pair of rulers with respect to the reference line can be made to coincide with the angle of the predetermined value regardless of the direction in which the head is oriented as if the rulers moved in parallel motion.

Another object of the invention is to provide a drawing apparatus comprising angle detection means mounted in the head for detecting an angle formed by a predetermined one of the pair of rulers with respect to the reference line when the head is haphazardly place on the surface of the drawing board, and producing a signal which controls the direction in which the rulers are oriented and causes the predetermined one of the pair of rulers to form an angle of a predetermined value with respect to the reference line.

Another object of the invention is to provide a drawing apparatus comprising an angle detector mounted in the head and utilizing the directivity of a float in a fluid for detecting an angle formed by the predetermined one of the pair of rulers with respect to the reference line and producing a signal which controls the direction in which the rulers are oriented and causes the predetermined one of the rulers to form a an angle of predetermined value with respect to the reference line.

Another object of the invention is to provide a drawing apparatus comprising an angle detector mounted in the head and utilizing the directivity of a pendulum member for detecting an angle formed by the predetermined one of the pair of rulers with respect to the reference line, and producing a signal which controls the direction in which the rulers are oriented and causes the predetermined one of the rulers to form an angle of a predetermined value with respect to the reference line.

Another object of the invention'is to provide a drawing apparatus comprising an angle detector mounted in the head and utilizing the unidirectivity of a magnetic compass whose needle points to a direction parallel to the magnetic lines of force of the earth as means for detecting the angle formed by the predetermined one of the rulers with respect to the reference line, and producing a signal which controls the direction in which the rulers are oriented and causes the predetermined one of the rulers to form an angle of a predetermined value with respect to the reference line.

Still another object of the invention is to provide a drawing apparatus comprising an angle detector mounted in the head and utilizing a pressure responding element which responds to a change in the pressure of a liquid caused in the direction in which the rulers are oriented as means for detecting the angle formed by the predetermined one of the rulers with respect to the reference line, and producing a signal which controls the direction in which the rulers are oriented and causes the predetermined one of the rulers to form an angle of a predetermined value with respect to the reference line.

Still another object of the invention is to provide a drawing apparatus comprising an angle detector mounted in the head and utilizing a potentiometer whose resistance shows a change when there is a change in the direction in which the rulers are oriented as means for detecting the angle formed by the predetermined one of the rulers with respect to the reference line, and producing a signal which controls the direction in which the rulers are oriented' and causes the predetermined one of the rulers to form an angle of a predetermined value with respect to the reference line.

Still another object of the invention is to provide a drawing apparatus comprising a suction device disposed under the head having no outside supporter for detachably attaching the head to the surface of the drawing board by the drawing force exerted by the suc- 

1. A drawing apparatus comprising a head adapted to be placed on the surface of a drawing board without requiring any outside supporter, said head comprised of a base of a shape adapted for positioning the head on the surface of the drawing board and a rotary member rotatably connected to said base, at least one ruler connected to said rotary member, angle deviation detection means disposed on the rotary member for detecting an angular deviation of a directional line defined by said rotary member from a predetermined imaginary reference line and producing an angular deviation signal responsive to detection of angular deviation between said lines, drive means built in said head for angularly rotating said rotary member, and control means coupled to said angle deviation detection means and said drive means for automatically controlling the direction and amount of angular rotation of said rotary member based on the angular deviation signal produced by said angular deviation detection means, whereby the directional line of the rotary member can be made parallel to the reference line.
 2. A drawing apparatus according to claim 1 wherein said angle deviation detection means comprises an angle detector including a magnetic needle pivotally supported in a case so that the magnetic needle may be oriented in the direction of magnetic poles of the earth and adapted to detect an angular deviation of the directional line of said rotary member from the direction in which the magnetic needle is oriented.
 3. A drawing apparatus according to claim 1 further comprising suction means disposed on the underside of said base and adapted to be brought into engagement with the surface of the drawing board, whereby the head can be brought into and out of intimate engagement with the surface of the drawing board by the drawing action of said suction means.
 4. A drawing apparatus according to claim 1 further comprising means for firmly fixing said rotary member to said base for preventing rotation of said latter relative to the former when an external force is exerted, as by the pressure of a pen, on said at least one ruler connected to the rotary member.
 5. A drawing apparatus according to claim 1 further comprising a power transmission and speed reducing mechanism operatively connecting said rotary membeR to said base, said power transmission and speed reducing apparatus performing the function of preventing inadvertent rotation of the rotary member due to pressure applied to said at least one ruler, as by a pen.
 6. A drawing apparatus according to claim 5 further comprising a mechanism for adjusting the position of said at least one ruler relative to the imaginary reference line which is capable of moving, conjointly with the angle deviation detection means, an angle indication line indicating the angular position of the angle deviation detection means with respect to the rotary member when an angle is selected at which the angle deviation detection means is disposed with respect to the rotary member.
 7. A drawing apparatus according to claim 1 wherein said angle deviation detection means comprises a potentiometer including a curved tube having sealed therein a suitable amount of a liquid conductor and an electric resistance wire arranged in said curved tube, said angle deviation detection means being capable of detecting an angular deviation of the directional line defined by said rotary member from the reference line based on a change in the value of resistance of said potentiometer when the surface of the drawing board is inclined with respect to the horizontal.
 8. A drawing apparatus according to claim 1 wherein said angle deviation detection means comprises a plurality of pressure sensitive elements each mounted at one of opposite ends of a curved tube having a fluid sealed therein, said angle deviation detection means being capable of detecting an angular deviation of the directional line defined by said rotary member from the reference line based on a change in the values of resistance of said pressure sensitive elements.
 9. A drawing apparatus comprising a head adapted to be placed on the surface of a drawing board without requiring any outside supporter, said head comprised of a base of a shape adapted for positioning the head on the surface of the drawing board, a rotary member rotatably connected to said base, angle deviation detection means for detecting an angular deviation directional line defined by said rotary member from a predetermined imaginary reference line and producing an angular deviation signal responsive thereto, drive means built in said head for angularly rotating said rotary member, and control means built in said head and coupled to said drive means and said angle deviation detection means, and adapted automatically to control the direction and amount of angular rotation of said rotary member based on the angular deviation signal produced by said angle deviation detection means so as to render said angular deviation signal zero, and at least one ruler connected to said rotary member.
 10. A drawing apparatus according to claim 9 wherein said angle deviation detection means comprises a strain gauge including a flexible plate member supported at one end by said rotary member and oriented in a predetermined direction at its free end at all times, and a plurality of resistors made of metallic foil and mounted on opposite sides of the plate member, said angle deviation detection means being capable of detecting an angular deviation of the directional line defined by said rotary member from the reference line based on a change in the value of resistance of said strain gauge.
 11. A drawing apparatus according to claim 9 wherein said angle deviation detection means comprises a unidirectional member mounted on said rotary member, a plurality of light receiving elements mounted on one of said rotary member and said unidirectional member and a light source mounted on the other of said unidirectional member and said rotary member, said light source being spaced apart from said light receiving elements an equal distance, said angle deviation detection means being capable of detecting an angular deviation of the directional line defined by said rotary member from the reference line based on a position in which the light emanating from said Light source is incident on one of said light receiving elements.
 12. A drawing apparatus comprising a head adapted to be placed without requiring any outside supporter on the surface of a drawing board inclined with respect to the horizontal, said head comprised of a base of a shaped adapted for positioning said head on the surface of the drawing board, a rotary member rotatably connected to said base, an angle deviation detector means connected to said rotary member and comprised of a float pivotally supported in a case containing a liquid therein, said angle deviation detector means being capable of detecting an angular deviation of a directional line defined by said rotary member from a direction in which the float is oriented and producing an angular deviation signal responsive thereto, drive means built in said head for angularly rotating said rotary member, and control means built in said head and coupled to said angle deviation detector means and said drive means and adapted automatically to control the direction and angular amount of rotation of said rotary member based on the angular deviation signal produced by said angle deviation detector means so as to render said angular deviation signal zero, and at least one ruler connected to said rotary member.
 13. A drawing apparatus comprising a head adapted to be placed without requiring any outside supporter on the surface of a drawing board inclined with respect to the horizontal, said head comprised of a base of a shape adapted for positioning said head on the surface of the drawing board, a rotary member rotatably connected to said base, an angle deviation detector means connected to said rotary member and comprised of a pendulum pivotally supported at the eccentric portion of said pendulum in a case, said angle deviation detector means being capable of detecting an angular deviation of a directional line defined by said rotary member from a predetermined direction in which the pendulum is oriented and producing an angular deviation signal responsive thereto, drive means built in said head for angularly rotating said rotary member, and control means built in said head and coupled to said drive means and said angle deviation detector means and adapted automatically to control the direction and amount of angular rotation of said rotary member based on the angular deviation signal produced by said angle deviation detector means so as to render said angular deviation signal zero, and at least one ruler connected to said rotary member.
 14. A drawing apparatus comprising a head adapted to be placed on the surface of a drawing board without requiring any outside supporter, said head comprised of a base of a shape adapted for placing said head on the surface of the drawing board, a rotary member rotatably connected to said base, angle deviation detection means connected to said rotary member for detecting an angular deviation of a directional line defined by said rotary member from a predetermined imaginary reference line and producing an angular deviation signal responsive thereto, an angle selection mechanism for freely selecting and setting the rotary member at any angle as desired at which said angle detection means is disposed with respect to said rotary member no matter in what position the head may be disposed on the surface of the drawing board, drive means built in said head for angularly rotating said rotary member, and control means coupled to said angle deviation detection means and adapted automatically to control the direction and amount of angular rotation of said rotary member based on the angular deviation signal produced by said angle deviation detection means so as to render said angular deviation signal zero, and at least one ruler connected to said rotary member.
 15. A drawing apparatus according to claim 14 further comprising an angle guide mechanism for guiding an operator by the sense of touch when said angle selection mechanism is actuated to select and set the apparatus at any aNgle as desired at which said angle deviation detection means is disposed with respect to the rotary member, no matter in what position the head may be disposed on the surface of the drawing board.
 16. A drawing apparatus comprising a head adapted to be placed in the surface of a drawing board without requiring any outside supporter, said head comprised of a base of a shape adapted for positioning the head on the surface of the drawing board and a rotary member rotatably connected to said base, a motor built in said head for angularly rotating said rotary member relative to said base, angle deviation detection means for detecting an angle formed by the directional line defined by said rotary member with respect to a predetermined imaginary reference line and producing an angular deviation signal, an electronic circuit for controlling the motor and coupled thereto, said circuit adapted to produce a starting signal and a stop signal for said motor based on an angular deviation signal produced by said angle deviation detection means to control the rotation of the motor so that the directional line of said rotary member can be made parallel to the predetermined imaginary reference line, said electronic circuit being further adapted to impress for an instant a reverse voltage signal on said motor simultaneously as said stop signal is produced and applied to the motor to interrupt its rotation, and at least one ruler connected to said rotary member.
 17. A drawing apparatus comprising a head adapted to be placed on the surface of a drawing board without requiring any outside supporter, said head comprised of a base of a shape adapted for placing the head on the surface of the drawing board, a rotary member rotatably connected to said base, angle deviation detection means comprised of a unidirectional member mounted on said rotary member, an iron core mounted on one of said unidirectional member and said rotary member and a differential transformer mounted on the other of said rotary member and said unidirectional member, said differential transformer and said iron core being disposed in spaced juxtaposed relationship, said angle deviation detection means detecting an angular deviation of a directional line defined by said rotary member from the direction in which said unidirectional member is oriented and producing an angular deviation signal by detecting the amount of displacement of said iron core from said differential transformer, and drive means built in said head for rotating said member in a direction and for an amount to render said angular deviation signal zero, and at least one ruler connected to said rotary member.
 18. A drawing apparatus comprising a head adapted to be placed on the surface of a drawing board without requiring any outside supporter, said head comprised of a base of a shape adapted for placing said head on the surface of the drawing board, a rotary member rotatably connected to said base and drive means built in said head for rotating said rotary member in any direction as desired, at least one ruler connected to said rotary member, at least two signal generators, at least one of which is mounted on said rotary member, signal detection means mounted on the drawing board for detecting signals produced by said signal generators, an arithmetic means for calculating an angular deviation of a directional line defined by said rotary member from a predetermined imaginary reference line based on the signals detected by said signal detection means and automatic control means for controlling the direction and amount of angular rotation of said rotary member so as to render zero an angular deviation signal produced by said arithmetic means. 